/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package cn.ziav.rpc.utils;

import static java.util.Collections.emptySet;
import static java.util.Collections.unmodifiableSet;

import java.util.AbstractSet;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;

/**
 * Miscellaneous collection utility methods. Mainly for internal use within the framework.
 *
 * @author william.liangf
 * @since 2.0.7
 */
public class CollectionUtils {

  private static final Comparator<String> SIMPLE_NAME_COMPARATOR =
      new Comparator<String>() {
        @Override
        public int compare(String s1, String s2) {
          if (s1 == null && s2 == null) {
            return 0;
          }
          if (s1 == null) {
            return -1;
          }
          if (s2 == null) {
            return 1;
          }
          int i1 = s1.lastIndexOf('.');
          if (i1 >= 0) {
            s1 = s1.substring(i1 + 1);
          }
          int i2 = s2.lastIndexOf('.');
          if (i2 >= 0) {
            s2 = s2.substring(i2 + 1);
          }
          return s1.compareToIgnoreCase(s2);
        }
      };

  private CollectionUtils() {}

  @SuppressWarnings({"unchecked", "rawtypes"})
  public static <T> List<T> sort(List<T> list) {
    if (isNotEmpty(list)) {
      Collections.sort((List) list);
    }
    return list;
  }

  public static List<String> sortSimpleName(List<String> list) {
    if (list != null && list.size() > 0) {
      Collections.sort(list, SIMPLE_NAME_COMPARATOR);
    }
    return list;
  }

  public static Map<String, Map<String, String>> splitAll(
      Map<String, List<String>> list, String separator) {
    if (list == null) {
      return null;
    }
    Map<String, Map<String, String>> result = new HashMap<>();
    for (Map.Entry<String, List<String>> entry : list.entrySet()) {
      result.put(entry.getKey(), split(entry.getValue(), separator));
    }
    return result;
  }

  public static Map<String, List<String>> joinAll(
      Map<String, Map<String, String>> map, String separator) {
    if (map == null) {
      return null;
    }
    Map<String, List<String>> result = new HashMap<>();
    for (Map.Entry<String, Map<String, String>> entry : map.entrySet()) {
      result.put(entry.getKey(), join(entry.getValue(), separator));
    }
    return result;
  }

  public static Map<String, String> split(List<String> list, String separator) {
    if (list == null) {
      return null;
    }
    Map<String, String> map = new HashMap<>();
    if (list.isEmpty()) {
      return map;
    }
    for (String item : list) {
      int index = item.indexOf(separator);
      if (index == -1) {
        map.put(item, "");
      } else {
        map.put(item.substring(0, index), item.substring(index + 1));
      }
    }
    return map;
  }

  public static List<String> join(Map<String, String> map, String separator) {
    if (map == null) {
      return null;
    }
    List<String> list = new ArrayList<>();
    if (map.size() == 0) {
      return list;
    }
    for (Map.Entry<String, String> entry : map.entrySet()) {
      String key = entry.getKey();
      String value = entry.getValue();
      if (StringUtils.isEmpty(value)) {
        list.add(key);
      } else {
        list.add(key + separator + value);
      }
    }
    return list;
  }

  public static String join(List<String> list, String separator) {
    StringBuilder sb = new StringBuilder();
    for (String ele : list) {
      if (sb.length() > 0) {
        sb.append(separator);
      }
      sb.append(ele);
    }
    return sb.toString();
  }

  public static boolean mapEquals(Map<?, ?> map1, Map<?, ?> map2) {
    if (map1 == null && map2 == null) {
      return true;
    }
    if (map1 == null || map2 == null) {
      return false;
    }
    if (map1.size() != map2.size()) {
      return false;
    }
    for (Map.Entry<?, ?> entry : map1.entrySet()) {
      Object key = entry.getKey();
      Object value1 = entry.getValue();
      Object value2 = map2.get(key);
      if (!objectEquals(value1, value2)) {
        return false;
      }
    }
    return true;
  }

  private static boolean objectEquals(Object obj1, Object obj2) {
    if (obj1 == null && obj2 == null) {
      return true;
    }
    if (obj1 == null || obj2 == null) {
      return false;
    }
    return obj1.equals(obj2);
  }

  public static Map<String, String> toStringMap(String... pairs) {
    Map<String, String> parameters = new HashMap<>();
    if (ArrayUtils.isEmpty(pairs)) {
      return parameters;
    }

    if (pairs.length > 0) {
      if (pairs.length % 2 != 0) {
        throw new IllegalArgumentException("pairs must be even.");
      }
      for (int i = 0; i < pairs.length; i = i + 2) {
        parameters.put(pairs[i], pairs[i + 1]);
      }
    }
    return parameters;
  }

  @SuppressWarnings("unchecked")
  public static <K, V> Map<K, V> toMap(Object... pairs) {
    Map<K, V> ret = new HashMap<>();
    if (pairs == null || pairs.length == 0) {
      return ret;
    }

    if (pairs.length % 2 != 0) {
      throw new IllegalArgumentException("Map pairs can not be odd number.");
    }
    int len = pairs.length / 2;
    for (int i = 0; i < len; i++) {
      ret.put((K) pairs[2 * i], (V) pairs[2 * i + 1]);
    }
    return ret;
  }

  /**
   * Return {@code true} if the supplied Collection is {@code null} or empty. Otherwise, return
   * {@code false}.
   *
   * @param collection the Collection to check
   * @return whether the given Collection is empty
   */
  public static boolean isEmpty(Collection<?> collection) {
    return collection == null || collection.isEmpty();
  }

  /**
   * Return {@code true} if the supplied Collection is {@code not null} or not empty. Otherwise,
   * return {@code false}.
   *
   * @param collection the Collection to check
   * @return whether the given Collection is not empty
   */
  public static boolean isNotEmpty(Collection<?> collection) {
    return !isEmpty(collection);
  }

  /**
   * Return {@code true} if the supplied Map is {@code null} or empty. Otherwise, return {@code
   * false}.
   *
   * @param map the Map to check
   * @return whether the given Map is empty
   */
  public static boolean isEmptyMap(Map map) {
    return map == null || map.size() == 0;
  }

  /**
   * Return {@code true} if the supplied Map is {@code not null} or not empty. Otherwise, return
   * {@code false}.
   *
   * @param map the Map to check
   * @return whether the given Map is not empty
   */
  public static boolean isNotEmptyMap(Map map) {
    return !isEmptyMap(map);
  }

  /**
   * Convert to multiple values to be {@link LinkedHashSet}
   *
   * @param values one or more values
   * @param <T> the type of <code>values</code>
   * @return read-only {@link Set}
   */
  public static <T> Set<T> ofSet(T... values) {
    int size = values == null ? 0 : values.length;
    if (size < 1) {
      return emptySet();
    }

    float loadFactor = 1f / ((size + 1) * 1.0f);

    if (loadFactor > 0.75f) {
      loadFactor = 0.75f;
    }

    Set<T> elements = new LinkedHashSet<>(size, loadFactor);
    for (int i = 0; i < size; i++) {
      elements.add(values[i]);
    }
    return unmodifiableSet(elements);
  }

  /**
   * Get the size of the specified {@link Collection}
   *
   * @param collection the specified {@link Collection}
   * @return must be positive number
   * @since 2.7.6
   */
  public static int size(Collection<?> collection) {
    return collection == null ? 0 : collection.size();
  }

  /**
   * Compares the specified collection with another, the main implementation references {@link
   * AbstractSet}
   *
   * @param one {@link Collection}
   * @param another {@link Collection}
   * @return if equals, return <code>true</code>, or <code>false</code>
   * @since 2.7.6
   */
  public static boolean equals(Collection<?> one, Collection<?> another) {

    if (one == another) {
      return true;
    }

    if (isEmpty(one) && isEmpty(another)) {
      return true;
    }

    if (size(one) != size(another)) {
      return false;
    }

    try {
      return one.containsAll(another);
    } catch (ClassCastException unused) {
      return false;
    } catch (NullPointerException unused) {
      return false;
    }
  }

  /**
   * Add the multiple values into {@link Collection the specified collection}
   *
   * @param collection {@link Collection the specified collection}
   * @param values the multiple values
   * @param <T> the type of values
   * @return the effected count after added
   * @since 2.7.6
   */
  public static <T> int addAll(Collection<T> collection, T... values) {

    int size = values == null ? 0 : values.length;

    if (collection == null || size < 1) {
      return 0;
    }

    int effectedCount = 0;
    for (int i = 0; i < size; i++) {
      if (collection.add(values[i])) {
        effectedCount++;
      }
    }

    return effectedCount;
  }

  /**
   * Take the first element from the specified collection
   *
   * @param values the collection object
   * @param <T> the type of element of collection
   * @return if found, return the first one, or <code>null</code>
   * @since 2.7.6
   */
  public static <T> T first(Collection<T> values) {
    if (isEmpty(values)) {
      return null;
    }
    if (values instanceof List) {
      List<T> list = (List<T>) values;
      return list.get(0);
    } else {
      return values.iterator().next();
    }
  }
}
